FDNY EMTs wheel a woman out of the YWCA in Brooklyn. EMTs were called in response to the fatal stabbing.William Farrington

The women of the Brooklyn YWCA had always been safe — until Saturday, when one of their own became a murderer and shattered a sense of security built over 128 years.

Liza Millett was stabbed 80 times Saturday by a down-the-hall neighbor who wielded a 6-inch kitchen knife.

Millett, 48, a native of the West Indies, had lived for years at the Brooklyn YWCA on Third Avenue near Atlantic Avenue, her neighbors said. She was known as a hard-working home health aide who loved to cook.

After the slaying, Millett’s enraged, agitated attacker, 56, fled to her own room just down the hall and briefly barricaded herself inside after the 7 a.m. slaying.

Cops responding to 911 calls found Millett “riddled with stab wounds” on her back, torso and arms, a source said. Its unclear what sparked the killing.

Paramedics rushed Millett to New York Methodist Hospital. Doctors there could not save her life.

Millett’s attacker has not been identified by police.

Members of the NYPD’s Emergency Service Unit took the suspect into custody and brought her to Kings County Hospital for a psychiatric evaluation, police said. Charges against her were pending.

Cops recovered the 6-inch knife at the scene.

It was the first homicide in the history of the Brooklyn YWCA, a spokeswoman said. Neither woman had a record of violence, the YWCA added.

“Our 24-hour on-site security responded to the incident immediately and no other residents were harmed,” the YWCA said. “Since our founding in 1888, the organization has never experienced a violent event within its community of residents.”